The mid-morning mind-frak springs from the highly advanced brain of Jan Westerhoff, a philosophy professor and metaphysics researcher at the University of Durham. In the ambitiously titled book Reality: A Very Short Introduction, Westerhoff breaks down why your present reality might not be so real:

We optimistically assume that you get eight hours of sleep a night, which leaves sixteen hours during which you are awake. Sleep researchers have found out that there is a strong correlation between dreaming and being in so-called REM (rapid eye movement) sleep. REM sleep is characterized by rapid movement of the eyeballs; the brain is highly active, its electric activity resembles that of a waking brain, but the sleeper is more difficult to wake than during slow-wave or non-REM sleep. We know that between 2-% and 25% of our sleep is REM sleep. Taking the lower value and assuming that you always and only dream during REM sleep, this gives us 1.6 hours of dreaming ever night. As there are therefore 1.6 hours of dream consciousness for every 16 hours of waking consciousness, this means that your chance of dreaming at any given moment is 1 in 10.

Your gut reaction, I know, is that this is silly and wrong. Me? I'd much rather assume I'm just dreaming about working on a Sunday, and that any minute I'll wake up to find myself swaddled in my Learjet, en route to my own private island for a month of riding grizzly bears and snorting rainbows. Pinch harder, dammit!. [Brain Pickings via Twitter]